Comparison of Morbidity Between Sentinel Lymph Node Biopsy and Elective Neck Dissection in Dogs With Head and Neck Malignancies

Elective neck dissection (END) and sentinel lymph node biopsy (SLNB) are suggested for nodal staging of canine head and neck malignancies (HNM). This study aims to compare the morbidity of END to SLNB. Seventy-six client-owned dogs with HNM that underwent END (n=28) or SLNB (n=48) in two institutions were retrospectively enrolled. Retrieved variables included data on signalment, lymph centre and lymph nodes, intra- and post-surgical complications (PSC) of lymphadenectomy, and histopathology results. The cumulative incidence of PSC at 30 days was estimated for END and SLNB and compared with Gray's test. The influence of variables on the incidence of complications was evaluated using univariate and multivariate models. No intraoperative complication occurred. The PSC were mostly mild. Seroma was the most frequent. The cumulative incidence of PSC of lymphadenectomy at 30days was 47.4%, and they were severe in 14% of cases. The incidence of PSC was 25% for SLNB and 85.7% for END, and the difference was statistically significant (p<0.001). Clinically enlarged nodes (p=0.03), institution (p = 0.03), increasing number of resected nodes (p < 0.001) and of lymph centres (p < 0.001) predicted a higher incidence of PSC in the univariate model. In the multivariate analysis, only the type of node management (END vs. SLNB) remained significant. Although lymphadenectomy is a well-tolerated procedure in dogs with HNM, END was correlated with a higher risk of PSC compared to SLNB. Stratification of dogs by the risk of multiple nodal metastases is warranted to identify those who may still benefit from END despite a higher PSC risk.